Physical Activity in Prevention of Coronary Heart Disease
- Varghese T, Schultz WM, McCue AA, et al.
- Physical Activity in the Prevention of Coronary Heart Disease: Implications for the Clinician. Heart 2016;102:904-909.
The following are key points for clinicians to remember about physical activity (PA) and the prevention of coronary heart disease (CHD):
- Physical activity (PA) is an independent and protective risk factor associated with reduced cardiovascular (CV) morbidity and mortality (odds ratio, 0.86; p < 0.0001), and inactivity accounts for 12.2% of the population-attributable risk for acute myocardial infarction (MI) and 6% of coronary heart disease (CHD) case,s with an estimated 0.68-year reduction in life expectancy. Because >40% of the risk reduction associated with exercise cannot be explained by changes in conventional risk factors including lipids, blood pressure, and glucose-insulin, it suggests a cardioprotective “vascular conditioning.”
- Guidelines recommend that clinicians use counseling interventions that include setting specific and short-term goals, providing feedback on progress, advocating strategies for self-monitoring, establishing a plan for frequency and duration of follow-up, using individually tailed interventions based on readiness to change and motivational interviewing, and enhancing patient self-efficacy. PA should include at least 30 minutes of moderate-intensity PA 5 days/week, 20 minutes of vigorous aerobic exercise 3 days a week or combinations, in addition to 2–3 days/week of resistance and flexibility exercise.
- The Exercise in Medicine campaign calls for PA to become standard of practice in health care, encouraging clinicians to evaluate their patients’ PA at every visit and “prescribe” exercise at appropriate “dosages.” Cost-effective nonphysician health coaches, pedometers/accelerometers, mobile applications, and social media provide increasing PA awareness, motivation, and monitoring of exercise progress.
- Exercise-based cardiac rehabilitation (CR) is the cornerstone for secondary prevention of CV disease (CVD). In contemporary exercise-based CR programs, the reported incidence of cardiac arrest and death approximate 1 in 115,000 and 1 in 750,000 patient-hours of participation, respectively. CR comprises several core components, including baseline patient assessment, nutritional and psychosocial counseling, risk factor management, PA counseling and exercise training. In patients with CHD, CR is associated with a 13% and 26% lower all-cause and CVD mortality and a 31% reduction in hospital admissions at 12 months. CR participation is also associated with improvements in CHD risk factors, reduced angina and depression, improved fitness, and enhanced health-related quality of life (QOL). However, in patients with acute MI and who were eligible for CR, only 62.4% were referred to CR at the time of hospital discharge, and only 23.4% of all patients actually attended one or more CR sessions in the year post-discharge. In patients with chronic heart failure (CHF) who are being optimally medically managed, exercise-based CR programs confer an additional 11% reduction in all-cause mortality and hospitalization, a 15% reduction in CV death and CHF hospitalization, and improved QOL.
- Prior to prescribing PA for patients with CHD, physicians should assess the patients’ exercise tolerance. Peak or symptom-limited exercise testing should be considered to establish a baseline fitness level, determine the prescribed heart rate range for training, and evaluate for exercise-induced myocardial ischemia or arrhythmias that may alter ongoing medical management. Recently discharged patients with CHD should be referred to CR for education, counseling and supervision, and monitoring of exercise training. After prescreening is completed to identify those in whom CR should be delayed or prohibited, the general recommendation for patients is 30–60 minutes daily of moderate-intensity PA for at least 5 days of the week and performed at an intensity of 40–80% of the peak heart rate.
- Can too much exercise be dangerous? There is a dose-response relation between exercise and CV-related mortality during long-term follow-up. Regular walking or running were associated with progressively lower CV mortality up to a point, beyond which much of the survival benefit was lost. The least physically active cohorts were at the highest risk for CV and all-cause mortality; and the most physically active subsets (high-intensity exercise at the greatest weekly dosage) were at increased risk of CV mortality as compared with more moderately active individuals. Interval training seems more effective than continuous exercise for the improvement of aerobic capacity in CHD, but additional long-term studies assessing safety, compliance, and morbidity and mortality following interval training are needed. In healthy persons, while “more is not always better,” it is not clear whether “more is actually worse.”
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